I have a 435cfm fan, 2 600w ballast and 3 fans hooked up to mine for 3 years and never a problem, I can even charge my cellphone at the same time. Its got a high amp rating. Very good timer. But as Sand sad, always try to keep 20% under.
Its better to water with lights on cuz you can see what your doing lol =P
I water anywhere form 30 min to 1 hour after lights come on. My dirt hasnt warmed up yet, everything is still nice from nighttime temps, and iirc thats when the plants are going to take up most of there water/food for...
I have never use a dome for seedlings, and I have never had a seedling die, now im NOT saying dont use one, just that I dont use em.
Clones, now thats a different story, a dome is a must.